BR Standard Class 3 2-6-2T - Design Details

Design Details

The design and construction took place at the ex-GWR Swindon Works, along with the 2-6-0 tender engine version of the class. Although the boiler shared flanged plates with the GWR No.2 boiler the barrel was shortened by 5 13⁄₁₆ inches and a dome added. Strangely they did not share the same design of wheels as the Doncaster-designed BR Standard Class 4 2-6-0 (76XXX), which also had 5 ft 3 in (1,600 mm) driving wheels and the same piston stoke, and hence crank-pin throw.

In common with a number of the other BR Standard Classes, the chassis design used a number of LMS-designed components including Brake Hanger Brackets, Flexible Stretcher Brackets and Reversing Shaft Brackets.

The cylinder covers of engines as built were fitted with "screw-in" type pressure relief valves. From September 1955 revised cylinder covers were introduced for renewals incorporating "bolt-on" type pressure relief valves.

Although the chassis had many almost identical parts to the LMS Ivatt Class 4 the motion brackets were derived from the design of those fitted to the LMS Ivatt Class 2 2-6-0 and LMS Ivatt Class 2 2-6-2T.

Unlike a number of the larger BR Standards the exhaust steam manifold within the smokebox saddle was a steel fabrication that was part of the welded saddle. In a number of the large BR standards (BR Standard Class 6 and Class 7 engines) the exhaust steam manifold was a steel casting welded into the saddle during manufacture.